Our library holds a copy of the Ander Theil of Johannes Agricola's Commentariorum, Notarum, Observationum & Animadversionum ... published in Leipzig in 1639 (Ferguson, v. I, p. 12). There is an inscription on the flyleaf in the hand of a previous owner, probably John Winthrop, Jr. (1606-1676), who read widely on and practiced alchemy: "page 369: Brentius scripsit Farraginem Tincturarum Physicarum."
There is indeed mention on p. 365 of Brentius and a work with that title by him; my German is not up to the task of understanding more than that. Brentius is almost certainly the theologian Johan Brenz, but I've had no luck in tracking down a work by him with the above title, or any variation on it that I can come up with.
Can anyone cast some light on this matter? It would be very useful to us to know why this topic was of interest to Winthrop.
